1. Technical Field
The present disclosure relates to a transmission system, a transmission device, and a data transmission method.
2. Related Art
Two-way communication using the WebSocket standard is one method of exchanging data between a plurality of devices as described in JP-A-2012-182744. Each time data is stored in the storage unit of the server in the configuration disclosed in JP-A-2012-182744, data is sent from the server to a client device. This configuration enables transmitting data without the client device requesting data from the server.
However, when data is transmitted without the device on the side that receives the data asserting a request for the data, it is not easy to determine which client device the data should be sent to because the receiving side does not request the data. The connection between the devices must therefore be simple to unconditionally determine the device to which data is sent, for example, such as by a 1:1 connection between the sending device and the receiving device, as described in JP-A-2012-182744. The relationship between the sending device and the receiving device is therefore limited with the technology of the related art.
In a system in which a server device transmits data, processes such as resending data that was already sent is normally controlled by the server. In this event, the server must store the transmitted data. As a result, achieving a configuration that can respond to retransmission requests from a client is difficult.